Piper Perabo Engaged to Stephen Kay

There's nothing covert about it: Piper Perabo is engaged to her director-producer beau Stephen Kay, PEOPLE has exclusively learned.

"They're very happy," a source who knows the couple says of the Covert Affairs star and Kay, who is a director on the hit USA Network series.

New Zealand-born Kay, who previously worked as an actor on shows like General Hospital, is also a co-executive producer of the show. The final six episodes of season four will resume Oct. 17 after a four-week hiatus.